Synthesis of uniform silica particles with controlled size by organic amine base catalysts via one-step process

Uniform silica particles were synthesized by synergistic combination of sodium 4-styrene sulfonate (NaSS) anionic surfactant and organic amine base catalyst such as ethylenediamine (EDA) or diethylenetriamine (DETA). The EDA and DETA organic amine base catalysts could promote the growth reaction rate so that they produced larger silica particles compared to the NH₄OH base catalyst because the organic amines provide more basic micro-environment near the surface of the silica particle due to multiple amine groups in a single molecule. Accordingly, the size of the silica particle was 450 ± 12 nm (NH₄OH), 725 ± 21 nm (EDA), and 942 ± 130 nm (DETA) in similar pH conditions.